Contradiction with Mark 16:5
Mark describes a young man inside the tomb, whereas Matthew 28:2 mentions an angel outside the tomb.
Mark 16:5: And entering into the sepulchre, they saw a young man sitting on the right side, clothed in a long white garment; and they were affrighted.
Contradiction with Luke 24:4
Luke mentions two men standing by in shining garments, whereas Matthew 28:2 describes a singular angel with a countenance like lightning.
Luke 24:4: And it came to pass, as they were much perplexed thereabout, behold, two men stood by them in shining garments:
Contradiction with John 20:12
John describes two angels sitting inside the tomb, whereas Matthew 28:2 describes one angel outside the tomb.
John 20:12: And seeth two angels in white sitting, the one at the head, and the other at the feet, where the body of Jesus had lain.