Some of these levels just start out completely impossible.
• Starting out, your "special attack" is functionally useless since it only seems to stun enemies for one second, which is shorter than the recovery time of the attack itself; you'll stun an enemy, and they'll be right back to kicking your ass the next second as if nothing at all had happened.
• Even as soon as Level 2, the pair of raptors you end up fighting can easily swarm you and clip into your body, making it nigh impossible to attack them.
• When there's more than two enemies on screen at a time, it's incredibly easy to get stun-locked into submission...
• ...not to mention that, at the worst of times, the game likes to buffer inputs. If you're spamming one of your attacks, like the quick attack (Z) and want to switch to another, say your low kick (X), the game forces you to go through ALL OF THE PREVIOUS 'Z' ATTACKS YOU INPUT before moving onto the next set that you started.
• The game has no sense of direction... by which I mean that you can be in the middle of an attack, and your T-rex will start doing lightspeed pirouettes, flickering between looking left and right at incredible speeds (and often hitting nothing because of it).
• And sometimes, the game just loves to make you attack at random! I will have my hands completely off the Z/X/C/S buttons and just move around the screen, and it will occasionally make me do a quick attack at random until I let go; there's no rhyme or reason to it.
The only advice I can give? 'Z' and 'X' are the only two buttons you're going to be pressing for the entire game. If you're fighting raptors, low kick; if you're fighting parasaurs, quick attack. If you are lucky enough to get some distance between you, crouch and use a few heavy attacks to try and knock them out quickly since it's one of your most damaging moves.
Oh, and one more thing: don't be surprised if the enemy dinos start running towards you and pummeling the shit out of you while you still have the pre-game timer on the screen. More than once have I been attacked helplessly by a swarm of dinos that got pushed out of their starting boundaries and wailed on me to no end.