It appears to be stuck in 1st from what I can see, correct? You need to move the shift rail on the right forward. Tried pushing the clutch pedal in while prying with a screwdriver? May just be bound up and not able to move because the clutch is engaged.
I had one M5OD get stuck in 4th (bought it that way) and disassembled the trans. The 3/4 slider ring has three little rectangle deals that pivot back and forth to engage the synchros, and they were quite worn and the ring would get stuck, it was simply impossible to shift back into any other gear or neutral without disassembling the trans. Additionally, the rear countershaft bearing had exploded and the balls had fallen out. The countershaft was no longer sitting square in the case and was resting on the bottom of the bearing.
If you can't get it back in neutral by any of the above tricks and the shift rails are more or less stuck solid, I'd really suggest pulling it and having a look inside... anything could be wrong with it at this point.