I've tried a number of things. I've tried shotgun-cannon-shotgun, but the shotguns just lack the firepower required in the final level. I've then tried rocket-cannon-rocket, but that leaves my sam's vulnerable for too long. I've tried then rocket-shotgun-rocket, and this kind of works better: I bring out serious firepower right away and the shotgun gets laggards as they approach, but this is hit-and-miss: if I ever lose any of the three that's a life lost.
Certainly, during the level I get to have all the cool items: the super-heplful Armor All, the critical Serious Bomb, the handy-for-emergencies Serious Damage and the not-that-helpful Serious Speed; however using one means giving up firing for a minion for the full turn. I even have a few of each spared from the previous stages (not as much as I'd have hoped though), but I find out I can't quite complete the four side fights without using them — and then I must face the final boss.
If the developers' aim was avoiding Too Awesome To Use, it's certainly working. I'm not sure that helps me finish the game, however.
I imagine there must be a reasonable way to finish the game, but the options seem kind of limited. How do I go about to solving this final level?