Thanks for all your comments!
I'm a bit wary about adding too many features as I don't want to (a) once again get into a position where the game will never get finished because there's an infinite list of stuff to add; and (b) I don't want to detract from the basic concept too much (less is more sometimes).
Saying that though, a few powerups will probably make it in as it would add a bit of variety and keep you on your toes a bit (especially in two-player mode).
I spent a bit of time last night constructing a second level (the first bit of work I've done on the game all week) so first and foremost I'm looking to get that done.
Oh, and yes, I do like the main character too - I'm sure that we could use him in future games, Dizzy-style...