this is exceedingly neat! i can't really say anything about the graphics and the overall visual style that wasn't already said - it's Really, Really Good; cohesive, clean and well-executed
the gameplay flows really well too - i found it really enjoyable, with well-thought-out interplay between how you dispose of enemies and what you get in return. none of the guns felt pointless or overpowered (okay, i guess the machine gun kiiinda does have one benefit that the other guns lack - it can whittle down enemies' health exactly to the point where they are a one-hit melee kill, thus allowing you much more control over which pickups you farm from that enemy). the dashing/teleporting mechanic was neat too - it did save me a few times from some hairy situations.
however, i do agree with acgaudette on running out of ammo feeling a bit off - i get why the ammo counts are low and it does help with the farm-health/farm-ammo duality going on in the gameplay but rummaging through your guns looking for one that's not empty while getting your face bitten off doesn't feel all that great (maybe separate ammo counters could help with this, maybe have the guns deal 1/2 damage or something when they're "empty" rather than just going "click" - there are many options to alliviate this)
all in all though, this game is great and i thoroughly enjoyed my time with it! great job!