Many say it's both. That's not a valid answer to such a question. =) I think both are important but that movement is where close games are won or lost. Some examples (sorry if this gets a bit confused among all versions and rankings...):
- M 0.7.7 used only a narrow RandomTargeting gun (due to a bug) combined with its better than average movement. It took it to #29 in the rankings. That's how important movement is.
- M 0.9.2 had a reworked, really lousy movement. It didn't qualify for top-50.
- M 0.9.5 Installed a completely reworked, really simple, movement system. Which made a difference of 26 positions in the rankings (#26). That's how important movement is.
- M 0.9.6 Placed #9. This was due to /TheImportanceOfPersistance?, but wouldn't have been possible without the improved movement system over earlier Marshmallows.
- M 0.9.6 and 0.9.7 still has big problems with it's CornerMovement. I think that if I fix this M could start competing for the #3 spot. (The key word in that sentence is "think" of course.)
Most of these versions of M have almost the same aiming system. Which is rather lame compared to many bots like SandboxDT, Cigaret, PrairieWolf, the Duelist series, Dalek, most of Albert's bots and ... (the list of bots with better aiming than Marshmallow is long). Yet M has run as a yo-yo up and down the rumble rankings. That's how important movement is.
Hopefully I have now found the movement system that will let me focus on aiming a while and really compete among the best bots. Yes, Targeting is important as well. Look at SandboxDT. It has the best movement of all robots combined with a top-10 gun.