Got my geeetech I3 to print but only to the glass no tape or

Got my geeetech I3 to print but only to the glass no tape or anything have ordered some buildtek stuff see how I get on with that. Anyway managed to print out a cube and it doesn’t look good I think it’s Z wobble I can clearly see the z threaded rods moving and I’m pretty sure I can see my nozzle moving about as well. I’ve took some pictures of the cube:

Just want to double check from people more experienced than me that this is in fact Z wobble and not something else? Sadly the cube came unstuck as it started doing the top layers. Seems to be some warping on the bottom layers obviously didn’t stick well to plain glass. If anyone can spot any other problems I’m thinking there is could you provide a solution please? I’ve ordered some lead screws to replace the threaded rods seem to be much better though I’m sure I’ll have problems getting the firmware set up to move the Z axis the correct amount as it’s different threads but hopefully will get rid of the z wobble. Also on the first photo I think, is that over extrusion on the lower portion of the cube or extreme amounts of z wobble?

voçe está usando abs ou pla ? ABS tem muita contração por isso os cantos dobram para cima. se for abs tente não deixar o vento do coller bater na peça. Eu deixei meu vidro áspero com um esmeril e uso spray de cabelo para colar a peça.

Looks like corners are warping from heat and contraction. The fresh layer cools and shrinks, pulling the lower layers up and inward. This eventually adds up, and suddenly, the next layer isn’t landing on anything.
Solution…
Part cooling fan.
Other potential improvements…
Possibly slightly lower nozzle temp, and a hotter bed, or heated build chamber.