As far as Contra clones go, Time Slip does a nice job.  Sure, the character runs slow as crap, but you cannot go wrong with the relentless infinite ammo gun.  This game has a bit more platforming than the average Contra game, though jumping is pretty spot on usually.  The graphics are pretty plain, and the sound is not very inspired. However, if you are a Contra fan, this is definitely one to check out.