If you can withstand the surprisingly hard difficulty level, you'll find that Turok: Evolution is actually quite a good side-scroller.
Turok: Evolution for the Game Boy Advance has more in common with the Metal Slug shooter series for the NeoGeo than it does with the console versions of Turok: Evolution. The GBA version of Turok is actually a side-scrolling shooter that requires instant, almost instinctive reactions. Throughout its 20 very difficult levels, you'll face heavy resistance from all sorts of gun-toting thugs--human, alien, and dinosaur alike. If you can withstand the surprisingly hard difficulty level, you'll find that Turok: Evolution is actually quite a good side-scroller.
Aside from solving a few puzzles and avoiding a few traps, the ultimate goal in Turok: Evolution is survival. Like in some classic coin-op arcade action games, the enemies in Turok for the GBA reappear constantly and are prone to scoring free hits against you. As such, your best strategy is to run toward the goal with guns blazing. It only takes one shot to down the majority of human opponents, but the aliens and dinosaurs generally require multiple direct hits. So you'd better be ready to shoot fast. In later levels, some of the enemies even have heat-seeking missile launchers strapped to their backs!
The similarities to Metal Slug are obvious and numerous. Human soldiers resemble the grunts in the Metal Slug arcade games, while Turok's close-ranged ax attack is a knockoff of the knife slash that Metal Slug's Marco and Fio perform in close combat. Likewise, whenever you slay opponents, they vanish in a shower of blood and flame that's nearly identical to the manner in which soldiers expire in Metal Slug.
Despite the similarities, Metal Slug definitely has a leg up on Turok: Evolution, because there's no Slug Tank in Turok. In fact, there are no vehicles at all. Nevertheless, the 16 different weapons you can acquire are all palpably similar to the weapons in SNK's Metal Slug series. The bullets fired from the pistol weapons are large and exaggerated, while the discharges of the machine guns and lasers are broad and thin. Even some of the settings, such as a desert base and a moving locomotive, share more than a passing resemblance to the locations in Metal Slug 2 and 3.
For all that it borrows from Metal Slug and a few other lesser arcade games, Turok: Evolution does bring some amount of originality to its formula. Most levels have shortcuts that can spare you a great deal of combat, and there are also health power-ups and berserk power-ups that let you tear off on wild killing sprees at frequent intervals. Although much of the action takes place from a traditional 2D side-scrolling viewpoint, the fourth level in each area features a boss battle that shifts the perspective into something more in line with the perspective of gun-based shooters like Silent Scope or Time Crisis. During these stages, you'll have to aim the crosshairs and take potshots at bosses who are often much larger than the screen--all while avoiding an onslaught of enemies and bullets from all sides.
In light of the all the onscreen action, the graphics in Turok: Evolution are nothing short of remarkable. Characters animate fluidly and the screen never stalls, regardless of the number of bullets or explosions. While we're busy drawing comparisons, that's definitely a nod in Turok's favor over Metal Slug, a game that frequently bogged down when the action picked up. Each of Turok's weapons has a variety of visual effects that accompanies its use, and all of the GBA's transparency and shading abilities are put to work. In one jungle area, for example, Turok is partially submerged underwater--and you can see his lower half only through a green, murky distortion. For the most part, the level designs are clever and avoid cookie-cutter status thanks to a number of turns, shortcuts, pitfalls, and ladders placed at frequent intervals.
On the other hand, the audio is more of what you'd expect from a handheld action game. The explosions and digitized screams that accompany each death are crisp and satisfying, but the music is only OK. You probably won't notice the game's tunes much, anyway, since many of the cries you'll hear are those of noisy dinosaurs waiting just ahead of your position, and they'll drown out the soundtrack.
The frequency of those cries actually ties into the game's predominant annoyance--its amazing difficultly. If not for unlimited continues and the fact that you restart each level from the beginning after you die, you could almost call it a quarter muncher. Enemies become stronger and more plentiful as the levels progress, and there are many traps and other cheap shots that you just won't be able to avoid until you've discovered them by falling prey to them. A few armor and guardian angel power-ups are available to carry you past some of the hairier situations, but you generally have to be flawless in order to clear most levels.
There's also the question of what comes next once you finish the game. If you manage to do so, there's nothing left to do but to play it again. Unfortunately, the numbing difficulty of each level eliminates the vicarious thrill that most people get from successive replays of an action game. You're never really allowed to just wail and pummel on groups of hapless opponents. The ability to play as two different characters, Turok or Djunn, adds a touch of variety, and the presence of a two-player simultaneous link mode is a significant bonus, but the utility and fun of these options is dampened by core gameplay that can be so challenging that it discourages multiple replays.
Turok: Evolution is a good game, with gorgeous visuals and abundant action. The unfair difficulty will be much too steep for some, but masochistic fans of classic side-scrolling shooters might not mind.