You can technically play SRB2 without strafe, but you're severely handicapping yourself and you'll find the game far more frustrating. The basic idea isn't to emphasize the mouse (although we should indeed suggest giving it a shot because it's better overall) but to emphasize strafing as an important gameplay mechanic.
Huh. I've been playing it wrong all along then. I'm one of those arrow keys guys. >_>
I HAVE switched to using WASD and the mouse in single player a few times (notably for the endgame bosses), but outside of those cases I've rarely felt that strafing would have helped that much more.
Hmm...Maybe it's time to try for more time attack Emblems while using strafing? Maybe that'll cut a few more critical seconds off my times...
As dirty as a word as it is, we've even been considering a tutorial level purely to make sure that players understand strafing before letting them loose on the game, because it's the type of thing that I don't think we can teach without explicitly talking about it.
If it's optional/skippable, but very heavily recommended by the game I'd totally go for some kind of short tutorial/sandbox level. There are lots of little things here and there that you either have to discover by accident or via the forums/wikia that might trip up new players (pressing spin to make the Air Shield give you a jump boost for example, although that could always be expressed vie Cecho when you pick one up or something), in addition to the strafing thing.
I do think that a tutorial is distasteful as I personally hate that type of thing, but I think we've gotten enough data to realize that being subtle and gentle about it isn't working.
I think there's really no way around the fact that if we want players to understand certain things that we can't teach by example, we're going to have to tell them. .
I understand the frustration. It's better to be able to organically peel back the mechanics and understand them without a tutorial outright telling you. Tutorials can really spoil immersion and engagement in the opening of a game. No one likes sitting in class.
Unfortunately, there are people out there who will not understand something, no matter how important, no matter how clear it is, unless you directly tell them.
*looks balefully at my friend who got stuck in my supposedly "idiot proof" easy mode for one of my games*
*Turns and looks balefully at some of the idiots playing Evolve and not understanding basic things*
Actually, on the subject of "show, don't tell", will there ever be some hint to show players that a wall isn't "knuckles-Climbable" until they try to climb it? Personally I'm just used to it at this point, but it's still a nasty surprise the first few times it happens, until you learn to try to predict where they'll happen.