Is there any tackling or blocking?

No. NFL FLAG is a non-contact game:

• Defenders stop the ball carrier by pulling a flag. They can dive to pull a flag but can't tackle, hold or run through the ball carrier, or try to strip the ball.
• No blocking or screening is allowed at any time, and offensive players near the ball carrier must stop moving once the ball crosses the line of scrimmage.
• Ball carriers can't jump, leap or hurdle another player, and can't flag guard (stiff-arm, drop a shoulder, elbow or head, or cover their flags with the ball or jersey).
• Ball carriers must try to avoid defenders who have already set their position.

Intentional physical play isn't permitted. If officials see intentional tackling, elbowing, cheap shots or blocking, the player is ejected from the game, at the officials' discretion, with no appeal.