So you want to know how to guaruntee a huge combo in training mode (kinda required up to 10 build a map accordin to these instructions:
starting from the top:
1:Build 1 full row of small spikes
2:Build 1 full of small blocks
3:build next row with small blocks eliminate the middle 4 blocks with open space and replace blocks next to middle with spikes.
4:build blocks around the spikes all the way down to bottom, leaving no room for anything.
5: save map and start training
6: force enemy comp onto spikes, making sure he doesnt fall off and is programmed to stand.
7: he should be bouncing off the spikes repeatedly, making your combo increase drastically. Afterwards, if you want to speed things up set speed to X1.5 (X2.0 is removed )
This can also be used for entertainement purposes in level 9 ffa brawl, set with smart bombs if you set it to stock mode doing this, game will never end.
The main reason the spikes are at the top is so the wii is forced to make your characters appear inside the box you made, ootherwise they would spawn on top in an un editable area. the middle spikes are there for combos, but you can remove them for another form of bombing fun. the top blocks may not be neccasary either.