Okay, I have a few criticisms.
1) Don't focus on chaingrabbing. It's pretty easy to do with Dedede if you just SCG and it's not really impressive, not even half as impressive as waveshining is. Making a video with so much of it is just redundant...
2) Why are some of these clips even included? Like... a lot of them are blatantly.. not combos, and not even seamless strings of attacks. Some clips simply look like random gameplay thrown in there in which you get a hit or two off.
3) You don't really utilize one of Dedede's greatest strentghs, and that is traveling far off stage in order to intercept recovering opponents. Watch Romeo's videos with Dedede and you'll see exactly what I mean. What you can do with Dedede is practically set up a barrier between the stage and them by doing an aerial (forward works), then jump and do it again, then jump and do it again as they recover. A lot of opponents can be stopped by this "wall"
Not only does the barrier thing work, but Dededes back aerial strings together nicely in the air, so when someones off the stage in the air you should try to land a few on them.
You play a good Dedede, I would just make the video have different focuses next time. Especially a bit less chaingrabbing, unless it sets up for like some monstrous off-stage combo.